314: Scientific Intelligence. 



to the instrument builder, as well as instruction in the arts of 

 forging, soldering, glass-blowing and cutting, lacquering, etc. 

 In addition there are many useful hints on the working and 

 handling of materials such as quartz, amber and porcelain. The 

 camera and dark-room as adjuncts of the lecture, especially the 

 making of slides and the art of photo-micrography, are exten- 

 sively treated. In fact, one can hardly think of anything in the 

 organization and equipment for this side of physical instruction, 

 from the clerical work of the office to the chemical room, that is 

 not treated. Altogether this is a most valuable book. l. p. w. 



II. Geology. 



1. Recent Studies of the Moon's Features (Communicated by 

 J. Barrell). — Within the past year have appeared two notable con- 

 tributions to the literature of the moon's surface. One is by Pro- 

 fessor N. S. Shaler,* the other by Professor W. H. Pickeringf and 

 they represent divergent views. Professor Shaler remarks in the 

 Preliminary Note : a The ends sought have been those alone which 

 had distinct reference to geology. . . In fact almost all the ques- 

 tions brought up by studies on the satellite are more or less 

 entangled with those relating to the evolution of the planet, so 

 that except for the detailed account of the features of either 

 body they must needs be considered together. These features 

 may be compared by types, and in the main the following essay 

 consists of such comparisons." 



The craters are so different in size from those of the earth, 

 many being over a hundred miles in diameter, and so numerous, 

 overlapping and irregularly distributed that the causes leading 

 to their formation must be very different from those of volcanoes 

 upon the earth, and for these forms Shaler proposes the name of 

 vulcanoids. The maria, or great plains, evidently belong to a 

 category distinct from the vulcanoids, being characterized by their 

 larger size, smoother and darker floors, and it is suggested that 

 they may be caused by the infalling of large meteors. It would 

 seem, however, that the attempt to provide a meteoric origin for 

 the maria, but not for the craters, would lead into grave difficul- 

 ties. While the evident fluidity of the lavas which formed 

 them distinguishes them sharply from the steep, rough walls of 

 the vulcanoids, yet in degree of fluidity and in area covered they 

 have not so far exceeded the great lava flows of the western 

 United States and the Deccan of India. The mountainous reliefs 



*A Comparison of the Features of the Earth and the Moon, by N. S. 

 Shaler, Professor at Harvard University. Smithsonian Contributions to 

 Knowledge, vol. xxxiv, 79 pp., 24 plates. 



f "The Moon, a Summary of the Existing Knowledge of our Satellite, 

 with a complete Photographic Atlas," by William H. Pickering of Harvard 

 College Observatory. 103 pp., 100 plates. New York, Doubleday, Page & Co. 

 The text is a semi-popular treatment of matter already published in vols, 

 xxxii, part I, 1895, part II, 1900 and vol. li, 1903 Annals of the Astronomi- 

 cal Observatory of Harvard College. 



